[hat_man]

Thanks for the advice both of you.

I do have a larger tire size on there now. I checked the speedo and odometer before the tire change and they were very minimally off. Just a hair over 1 mile for every 100 driven. I figured that was pretty good. The current set up is 5% oversized tires. I did the same math and checked after the change. IIRC it went up to something like 6.5 miles for every 100 driven. So I'm thinking the speedo and odometer are fairly "calibrated" from the factory. At least in my truck. Vehicles are production line products and there are always some variances. Mine must have been one of the "good" ones.

I'm going to pick up the rear end next weekend. Not sure when I'll get it into mine, but after some testing and many full tank runs, I'll post up some results.

Wish me luck.